Device for lubricating a tandem axle assembly with an interaxle differential

ABSTRACT

In a forward axle assembly of a tandem axle assembly including a carrier mounted to an axle housing which has a first chamber formed therein, a gear housing mounted on the carrier and forming a second chamber therebetween, a differential case mounted on the gear housing and forming a third chamber therebetween, an interaxle differential disposed in the third chamber for carrying and distributing the torque from an engine, transfer gears being disposed in the second chamber and operatively connected between the interaxle differential and the carrier, a ring and pinion gear assembly meshed with each other and disposed in the first chamber, the pinion gear being connected to one of the transfer gears, a lubricating device for the interaxle differential, the lubricating device comprising a lubricating oil passage for conducting the lubricating oil directly from the ring gear in the axle housing to the interaxle differential in the third chamber.

United States Patent .1191

Hyakumura 1 1 DEVICE FOR LUBRICATING A'TANDEM AXLE ASSEMBLY WITH ANINTERAXLE 21 Appl. No.: 239,613

[30] Foreign Application Priority Data 3,383,937 5/1968 Toenne et al.184/11 R X 3,618,711 11/1971 Vollmer 184/11 AX 3,532,183 10/1970 Shealy184/13 R X FOREIGN PATENTS OR APPLICATIONS 1,447,322 6/1966 France184/6.12

[4 1 Nov. 13, 1973 1,047,820 12/1958 Germany 184/6.12

Primary ExaminerManuel A. Antonakas Attorney-Richard C. Sughrue et al.

[57] ABSTRACT In a forward axle assembly of a tandem axle assemblyincluding a carrier mounted to an axle housing which has a first chamberformed therein, a gear housing mounted on the carrier and forming asecond chamber therebetween, a differential case mounted on the gearhousing and forming a third chamber therebetween, an interaxledifferential disposed in the third chamber for carrying and distributingthe torque from an engine, transfer gears being disposed in the secondchamber and operatively connected between the interaxle differential andthe carrier, a ring and pinion gear assembly meshed with each other anddisposed in the first chamber, the pinion gear being connected to 5Claims, 6 Drawing Figures BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to a forward axle assembly of a tandemaxle assembly including an interaxle differential, and more particularlyto a lubricating device for the interaxle differential or power dividerin the forward axle assembly.

2. Description of the Prior Art In a conventional tandem axle assembly,such as that disclosed, for example, in US. Pat. No. 2,870,854, thetandem axle assembly is located beneath the rear of a vehicle chassisand is equipped with a bevel gear interaxle differential mounted on theforward tandem drive axle assembly. The forward drive axle assembly andrearward drive axle assembly are positioned relatively close to eachother and constitutea tandem drive axle assembly. Each of the axleassemblies are connected to the vehicle chassis by the usual suspensionmeans. In the forward drive axle assembly, an interaxle differentialhousing is secured to an annular flange on the front of the carrierhousing and includes a rear section that houses the transfer gearingbetween the interaxle differential and the carrier. During rotation ofthe ring gear, the forward axle ring gear throws oil into a trough whichconducts the oil to a passage in intermediate idler gear shaft, andthence through this passage to the bearings. A hole is formed at one endof the trough and mates with an aligned hole in the interaxledifferential rear housing section to permit part of the oil in thetrough to run into the bottom of the rear housing section. This oil ispicked up by the transfer gears and thrown into a longitudinal sidetrough integrally formed in the upper portion of the rear housingsection. The upper trough is inclined forward and downward to divert oilthrough an opening in thewall intothe interaxle differential chamberbetween the housing sections. v t

Several relatively large-diameter oil holes are formed in the forwardmember of the interaxle differential cage to lubricate the interaxledifferential gears. Excess oil from the interaxle differential housingflows back into the rear section and then passes through the pinionshaft bearings into the axle housing. In such a structure, the oilpasses through various intermediate means and paths from the ring gearchambers to the interaxle dif ferential housing, thus resulting in awaste of the oil along the path of travel. Furthermore, the structure ofthe oil passage is complicated and costly to manufacture.

SUMMARY OF THE INVENTION vice for lubricating a tandem axle assemblyhaving a 111- bricating oil passage directly connected from an axlehousing to. the interaxle differential housing to directly introducelubricating oil from the axle housing to the interaxle differentialhousing. I

It is still another object of this invention to provide a device forlubricating a tandem axle assembly with an interaxle differential whichis simple in structure.

A further object of this inventionis to provide a lubricating oilpassage continuously connected from the axle carrier housing directly tothe interaxle differential housing and formed at an upper portion of thehousings for directly introducing the lubricating oil contained in theaxle housing into the interaxle differential housing.

A still further object ofthis invention is to provide a part of thelubricating oil passage at the upper portion of the gear housing andformed in a trough shape for easily gathering the lubricating oildischarged from the transfer gear in the trough whereby the oil supplyamount is further increased together with the oil fed from the axle ringgear.

It is still another object of this invention to provide an additionallubricating oil passage for receiving the lubricating oil dischargedinto the transfer gear housing and introducing it into the interaxledifferential housing at the upper side of another side of the gearhousing for effectively utilizing the lubricating oil discharged fromboth of the ring gear housing and the transfer gear housing, in additionto the first lubricating oil passage.

These and other objects, features and advantages of this invention willbecome apparent from the following description taken in conjunction withthe accompanying drawings:

BRIEF DESCRIPTION OF THE DRAWINGS .FIG. 6 is a-sectional view of thelubricating oil passage taken along the line VI-VI in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,particularly to FIG. 1, which shows a sectional view of the front axleassembly of a tandem axle assembly provided with one embodiment of adevice for lubricating the tandem axle assembly therein constructedaccording to this invention, an axle housing 1 has a cover la fixed tothe rear portion thereof. An axle carrier assembly 2 is mounted to thefront portion of the housing I, and a transfer gear housing 3 is mountedto the 'front portion of the carrier 2; a case 4 housing the interaxledifferential is mounted to the front portion of the transfer gearhousing 3.

A first chamber 20 is formed by the axle housing 1 and the carrier 2,and a second chamber 30 is formed by the carrier 2 and the gear housing3; a third chamber 40 is formed by the gear housing 3 and the case 4. A

wall 2a for forminga partition between the first and second chambers isprovided. on the carrier 2, while a second wall 3d forming a partitionbetween the second and third chambers is provided on the gear housing 3.

An interaxle differential 6 for distributing the torque from an engineis supported in the third chamber 40 by bearings 31 and 41. Transfergears 7 and 8 are supported in mesh with each other in the secondchamber 30 by bearings 31, 33 and 21, 32, respectively. Transfer gear 8is fixed to a pinion shaft 9 which is extended into the first chamber 20and is connected to a pinion 10. Pinion 1b is meshed with a ring gear 11 for transmitting the torque to a wheel (not shown).

One of the output side gears 64 in the interaxle differ ential 6 isconnected to transfer gear 7, and the other output side gear 63 isconnected to a shaft 12 extended through the axle housing 1 and the gear7. The shaft 12 is connected to a pinion (not shown) of the rear axleassembly. The torque of the engine is, therefore, transmitted to thefront and rear axle assemblies of the tandem axle by the interaxledifferential assembly 6.

Lubricating oil is contained in the bottom of the first chamber 20, andpart of the ring gear 11 is always immersed in the lubricating oil.

In the tandem axle structure of the present invention, one means forintroducing lubricating oil into the interaxle differential is somewhatsimilar to that disclosed in U. S. Pat. No. 2,870,854. According to thisstructural feature, the lubricating oil in the first chamber 20 isconveyed by the ring gear 11 to a trough or passage formed in thecarrier, and is then introduced into the second chamber 30. Thelubricating oil accumulated in the second chamber 30 is thrown to atrough at the upper portion of the gear housing by the transfer gears,and is then introduced into the third chamber 40 to lubricate theinteraxle differential assembly 6.. The excessive oil in the thirdchamber 40 is returned through a proper escape hole provided in the wall3a partitioning the chambers 30 and 40 into the chamber 30. Theexcessive oil in the chamber 30 is returned through the bearing 21supporting the shaft 9 of the pinion into the chamber 20.

As shown by the two-dot chain line in FIG. 1, a continuous lubricatingoil passage 13 is provided at the upper portions of each of the threechambers 20, 30 and 40. The continuous passage 13 consists of a passage14 formed at the upper portion of the carrier 2 and a passage 15 formedat the upper portion of the transfer gear housing 3.

The cross sectional shape of the passage 14 is a box shape as shown inFIG. 6. One end of the passage 14 opens adjacent the path of rotation ofthe ring gear 11, while the other end thereof communicates with one endof the passage 15. The cross sectional shape of the passage 115 is atrough shape configuration, as shown in FIG. 2, with one end thereofcommunicating with one end of the passage 14 as previously described,white the other end thereof opens in the third chamber While the vehicleis running, that is, while the ring gear 11 is rotating, part of thelubricating'oil adhering thereto is discharged into the open end of thepassage I 14. This lubricating oil flows through the passages 14 and 15into the third chamber 40, having the interaxle differential 6 retainedon the bottom thereof. Holes 61 and 62 are formed in the carrier of theinteraxle differential 6, and the oil in the third chamber 40 flows intothe interaxle differential 6 through the holes 61 and 62 to lubricatethe elements therein requiring lubrication.

The excess oil in the third chamber 40 flows through a.

hole (not shown) formed in the wall 3a between the second and thirdchambers 30 and 40 or the bearings 31 for supporting one end of theinteraxle differential 6 into the second chamber 30 and is retained inthe bottorn thereof. The lubricating oil passing into the bottom of thesecond chamber 30 serves to lubricate the transfer gears 7 and 8. Sincepart of the gear 8 is always immersed in the lubricating oil retained onthe bottom of the second chamber 30, they are lubricated by the rotationof the gears 7 and 8. The excess lubricating oil in the second chamber30 returns into the first chamber 20 through the bearing 21 supportingthe pinion shaft 9 or through a hole (not shown) formed in the wall 211between the chambers 20 and 30.

The direction of rotation of the transfer gears 7 and 8 are shown byarrows in FIG. 2. The oil accumulated in the bottom of the chamber 30 isdischarged by the gears into the upper portion of the chamber 30, i.e.,the upper portion of the gear housing 3. Part of the oil flows into thetrough 15 to increase the amount of lubricating oil fed into theinteraxle differential 6..

In order to obtain a positive flow of the lubricating oil dischargedfrom the transfer gear into the trough shaped passage 15, a projection16 is formed at the open portion of the trough 15 of the upper portionof the slot 17 for receiving the oil, as seen in FIG. 3. Part of thelubricating oil discharged from the gear 7 is received by the projection16 to positively flow into the trough 15.

To further increase the amount of lubricating oil supplied into theinteraxle differential 6, a second trough shaped passage 15b is formedon the side of the upper portion of the gear housing 3 opposite a firstpassage 15a, as shown in FIG. 4. Since the direction of rotation of thegear 7 is as shown by the arrow, most of the lubricating oil dischargedtherefrom is received by the passage 15b rather than the passage 15a inFIG. 4. The passage 15b is so constructed as to introduce thelubricating oil therein into the third chamber 40. Therefore, even ifthe one end of the passage 15b is blocked by the wall 2a, the other endis so formed as to open in the chamber 40. The passage does not alwayshave to have a trough shaped configuration because most of thelubricating oil discharged from the transfer gear 7 is received by thepassage 15b to be fed into the third chamber 40.

' In comparison with FIG. 2, the embodiment shown in FIG. 5 includes anintermediate idler gear 71 provided between the transfer gears 7 and 8.Accordingly, the ring gear 11 is disposed on the opposite side of thepinion 10 to obtain the same rotating direction as the ring gear 11 inFIG. 2. The embodiment of FIG. 5 incorporates the same lubricatingstructure and overall gearing mechanism as that shown in FIG. 1 andaccordingly the representation and description of the structurecorresponding to FIG. 1 is omitted here.

The following description of the embodiment of FIG. 5 will be made withreference to the details of FIG. 1 incorporated therein. In the tandemaxle assembly of FIG. 5, the location of the passage 13 continuouslyformed between the chambers 20 and 40 is the same as that shown inFIG. 1. This passage 13 is formed at the upper portion of the carrier 2and the gear housing 3 on the side opposite to that shown in FIG. 2. Thepassage is of trough shaped configuration. Since the slot 17 is sodisposed as to face the rotating direction of the gear 7, the amount ofthe lubricating oil discharged from the gear 7 collected in the passage15 is more than that of the embodiment shown in FIG. 2. This lubricatingoil is discharged from the ring gear 11, and is fed into the chamber 40together with'the oil collected in the passage 14 so as to lubricate theinteraxle differential 6. The cross sectional shape of the passage 14 issimilar to that shown in FIG. 6.

In order to receive the oil discharged from the transfer gear 7, thecross sectional shape of the passage 15 shoule be of the trough shapedconfiguration having a slot 17 in the side thereof. In the embodimentshown in FIG. 2, the amount of lubricating oil flowing into the passage15. is relatively less, so that cross sectional configuration may be ofthe shape shown in FIG. 6. The cross sectional shape of the passage 14may be either as shown in FIG. 6 or as shown in FIG. 2. The passage Mmay be of any shape and disposition for receiving the lubricating oilfrom the ring gear 11 so as to introduce the oil into the passage 15.

In the embodiment shown in FIG/2, the amount of lubricating oil flowinginto the passage of the gear housing is reduced. Accordingly, if asecond passage of trough shaped cross sectional configuration and havinga slot facing the rotating direction of the transfer gear is formed atthe upper side of the housing in addition to and opposite the firstpassage, as shown in FIG. 4, an oil supply volume similar to that ofFIG. 5 maybe obtained.

If the passage in the gear housing is formed as shown in FIGS. 4 and 5,the amount of lubricating oil supplied into the interaxle differentialis increased so that the interaxle differential will be sufficientlylubricated, even during high load-low speed operation of the vehicle.

If the passage is formed with a trough shaped cross sectionalconfiguration having a projection as shown in FIG. 3, the decreasedamount of lubricating oil collected due to the rotating direction of thetransfer gear will be supplemented.

It should be understood from the foregoing description that since thestructure for lubricating a tandem axle assembly having an interaxledifferential of the present invention includes a first lubricating oilpassage continuously formed from a first chamber in the carrier housingto a second chamber at the upper portions of the carrier and thetransfer gear housing to introduce the oil stored in the axle housingdirectly into'the interaxle differential by the ring gear, the amount oflubricating oil supplied into the interaxle differential is greatlyincreased over the amount of oil supplied by the prior art structures.It should also be understood that when the passage provided at the topof the transfer gear housing is formd with a trough shaped configurationto receive the lubricating oil discharged from the transfer gear, theamount of oil supplied is further increased together with the oil fedfrom the ring gear. As discussed hereinabove, particularly, when a slotin the passage is so disposed as to face the rotating direction of thegear as shown in FIG. 5, the amount of oil supplied is increased by theamount of oil received from the ring gear, in comparison with the priorart devices.

Also, in every embodiment of the present invention, since the passage isintegrally formed in the carrier and transfer gear housing, thestructure is simple and easy to manufacture.

What is claimed is:

I. In a forward axle assembly of a tandem axle assembly, said forwardaxle assembly including a carrier mounted in an axle housing and forminga. first chamher therebetween, a gear housing mounted on said carrierand forming a second chamber therebetween, a case mounted on said gearhousing and forming a third chamber therebetween, an interaxledifferential being disposed in said third chamber for distributing thetorque from an engine, transfer gears being disposed in said secondchamber and operatively connected between said interaxle differentialand said carrier, said carrier including a pinion and ring gear meshedwith each other and disposed in said first chamber, said pinion beingconnected with one of said transfer gears, and a lubricating device, theimprovement characterized in that said lubricating device comprises acontinuous lubricating oil passagemeans directly connected from saidaxle housing to said case housing said interaxle differential, saidcontinuous lubricating oil passage means comprising a first continuouslubricating oil passage directly connected from said axle housing tosaid case housing said interaxle differential and being formed at theupper portions of said carrier housing through said gear housing, and asecond continuous lubricatingv oil passage directly connected from saidtransfer gear housing to said interaxle differential housing and beingformed on the side of said transfer gear housing opposite said firstcontinuous lubricating oil passage.

2. In a forward axle assembly of a tandem axle, said forward axleassembly including a carrier mounted in' an axle housing and forming afirst chamber therebetween, a gear housing mounted on said carrier andforming a second chamber therebetween, a case mounted on said gearhousing and forming a third chamber therebetween, an interaxledifferential being disposed in said third chamber for distributing thetorque from an engine, transfer gears being disposed in said secondchamber and operatively connected between said interaxle differentialand said carrier, said carrier including a pinion and ring gear meshedwith each other and disposed in said first chamber, said pinion beingconnected with one of said transfer gears, and a lubricating device, theimprovement characterized in that said lubricating device comprises acontinuous lubricating passage meanshaving a first passage formed at anupper portion of said carrier housing and having one end opening nearthe rotation path of the ring gear and the other end of said firstpassage connecting with a second passage at an upper portion of the gearhousing, said secondpassage being formed at the upper portion of saidgear housing and having one end communicating with the other end of saidfirst passage and the other end of said second passage opening into thethird chamber.

3. The improvement according to claim 2, wherein said second passage isformed with a slot-like opening in its inside wall for receivinglubricating oil dispersed from said transfer gears, whereby the amountof oil supplied to said interaxle differential is increased togetherwith the oil fed from said ring gear.

4. The improvement according to claim 3, wherein said second passageincludes a projection formed at the upper portion of said second passageand positioned above said slot-like opening for effectively receivinglubricating oil dispersed from said transfer gears, whereby the amountof lubricating oil supply to said interaxle differential is furtherincreased together with the oil fed from said ring gear.

5. The improvement according to claim 2, further comprising a thirdcontinuous lubricating oil passage formed on the side opposite saidsecond passage and directly connected from said transfer gear housing tosaid interaxle differential housing, said third continuous oil passagefacing opposite the direction of rotation of one of said transfer gears.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. DatedNovember 13, 1973 Inventor(s) HirOYU-ki Y mU-ra It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Please insert the name and address of the assignee;

Isuzu Motors Ltd.

Tokyo, Japan Signed and sealed this 25th day of June 1974 (SEAL) AttestEDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents FORM PO'WSO (169) USCOMM-DC 60376-P69 9 11.5. GOVERNMENTPIHNTING OFFICE 2 l9" O3$5-334.

1. In a forward axle assembly of a tandem axle assembly, said forwardaxle assembly including a carrier mounted in an axle housing and forminga first chamber therebetween, a gear housing mounted on said carrier andforming a second chamber therebetween, a case mounted on said gearhousing and forming a third chamber therebetween, an interaxledifferential being disposed in said third chamber for distributing thetorque from an engine, transfer gears being disposed in said secondchamber and operatively connected between said interaxle differentialand said carrier, said carrier including a pinion and ring gear meshedwith each other and disposed in said first chamber, said pinion beingconnected with one of said transfer gears, and a lubricating device, theimprovement characterized in that said lubricating device comprises acontinuous lubricating oil passage means directly connected from saidaxle housing to said case housing said interaxle differential, saidcontinuous lubricating oil passage means comprising a first continuouslubricating oil passage directly connected from said axle housing tosaid case housing said interaxle differential and being formed at theupper portions of said carrier housing through said gear housing, and asecond continuous lubricating oil passage directly connected from saidtransfer gear housing to said interaxle differential housing and beingformed on the side of said transfer gear housing opposite said firstcontinuous lubricating oil pAssage.
 2. In a forward axle assembly of atandem axle, said forward axle assembly including a carrier mounted inan axle housing and forming a first chamber therebetween, a gear housingmounted on said carrier and forming a second chamber therebetween, acase mounted on said gear housing and forming a third chambertherebetween, an interaxle differential being disposed in said thirdchamber for distributing the torque from an engine, transfer gears beingdisposed in said second chamber and operatively connected between saidinteraxle differential and said carrier, said carrier including a pinionand ring gear meshed with each other and disposed in said first chamber,said pinion being connected with one of said transfer gears, and alubricating device, the improvement characterized in that saidlubricating device comprises a continuous lubricating passage meanshaving a first passage formed at an upper portion of said carrierhousing and having one end opening near the rotation path of the ringgear and the other end of said first passage connecting with a secondpassage at an upper portion of the gear housing, said second passagebeing formed at the upper portion of said gear housing and having oneend communicating with the other end of said first passage and the otherend of said second passage opening into the third chamber.
 3. Theimprovement according to claim 2, wherein said second passage is formedwith a slot-like opening in its inside wall for receiving lubricatingoil dispersed from said transfer gears, whereby the amount of oilsupplied to said interaxle differential is increased together with theoil fed from said ring gear.
 4. The improvement according to claim 3,wherein said second passage includes a projection formed at the upperportion of said second passage and positioned above said slot-likeopening for effectively receiving lubricating oil dispersed from saidtransfer gears, whereby the amount of lubricating oil supply to saidinteraxle differential is further increased together with the oil fedfrom said ring gear.
 5. The improvement according to claim 2, furthercomprising a third continuous lubricating oil passage formed on the sideopposite said second passage and directly connected from said transfergear housing to said interaxle differential housing, said thirdcontinuous oil passage facing opposite the direction of rotation of oneof said transfer gears.